test: use files for receiving Jest JSON output

.gitignore

@@ -10,6 +10,7 @@ node_modules
 # build artifacts
 /dist
 tsconfig.tsbuildinfo
+e2e/**/jest-output.json
 e2e/**/yarn.lock
 e2e/**/.pnp.*
 e2e/**/.vscode-test

clean-e2e.mjs

@@ -5,13 +5,16 @@ import url from 'url'
 import glob from 'fast-glob'
 import fs from 'fs-extra'
 
-const items = await glob(['e2e/*/(yarn.lock|.vscode-test|.pnp.cjs)'], {
-  cwd: path.dirname(url.fileURLToPath(import.meta.url)),
-  dot: true,
-  onlyFiles: false,
-  absolute: true,
-  followSymbolicLinks: false,
-})
+const items = await glob(
+  ['e2e/*/(yarn.lock|.vscode-test|.pnp.cjs|jest-output.json)'],
+  {
+    cwd: path.dirname(url.fileURLToPath(import.meta.url)),
+    dot: true,
+    onlyFiles: false,
+    absolute: true,
+    followSymbolicLinks: false,
+  }
+)
 
 for (const item of items) {
   await fs.remove(item)

e2e/utils.ts

@@ -94,26 +94,40 @@ export async function prepareDir(cwd: string): Promise<void> {
   )
 }
 
+async function gracefulReadFile(file: string): Promise<string> {
+  try {
+    return await fs.readFile(file, 'utf8')
+  } catch (e) {
+    return ''
+  }
+}
+
 export async function runJest(
   cwd: string,
   args: string[] = []
 ): Promise<execa.ExecaChildProcess & Promise<{ json: unknown }>> {
-  const results = await execa('jest', ['--json', ...args], {
-    cwd,
-    preferLocal: true,
-    timeout: 30000,
-    reject: false,
-  })
+  const results = await execa(
+    'jest',
+    ['--json', '--outputFile', 'jest-output.json', ...args],
+    {
+      cwd,
+      preferLocal: true,
+      timeout: 30000,
+      reject: false,
+    }
+  )
+  const outputFile = path.resolve(cwd, 'jest-output.json')
+  const output = await gracefulReadFile(outputFile)
 
-  if (results.stdout) {
+  if (output.trim()) {
     try {
-      const json = JSON.parse(results.stdout) as ActualAggregatedResult
+      const json = JSON.parse(output) as ActualAggregatedResult
       return {
         ...results,
         json: normalizeResults(json),
       }
     } catch (error) {
-      console.error(`Failed to parse jest output: ${results.stdout}`)
+      console.error(`Failed to parse jest output: ${output}`)
       throw error
     }
   }